Plus each group was working with a different photo- spectrometer machine. This means that there were four different machines with four different calibrations that are each producing slightly different data. One group's value of 0.01 might have come out to 0.02 on another machine. There were not enough samples as well. Grinding our own grass only added to the variables. On top of all that, the majority of the class was confused about the procedure and that could be the reason why the data does not show anything conclusive. Improving Procedure: More trials would have increased the accuracy of the experiment. Although it would take a longer period of time, using one machine to collect data from would also help. I were were wanting to further the procedure for a future experiment, I might test other plant species instead of just grass. This would give me a broader spectrum to draw conclusions from. It might also be interesting to comparatively test traditional indoor plants to outdoor plants. ...read more.

The first peak indicates the percentage of absorption of wavelengths that produce blue colour. The second peak for both graphs indicates the percentage of absorption of wavelengths that produce red colour. The minimum point of the percentage of absorption for both graphs indicates the absorption of wavelengths that produce green colour.